25 research outputs found
Miniaturized Transistors, Volume II
In this book, we aim to address the ever-advancing progress in microelectronic device scaling. Complementary Metal-Oxide-Semiconductor (CMOS) devices continue to endure miniaturization, irrespective of the seeming physical limitations, helped by advancing fabrication techniques. We observe that miniaturization does not always refer to the latest technology node for digital transistors. Rather, by applying novel materials and device geometries, a significant reduction in the size of microelectronic devices for a broad set of applications can be achieved. The achievements made in the scaling of devices for applications beyond digital logic (e.g., high power, optoelectronics, and sensors) are taking the forefront in microelectronic miniaturization. Furthermore, all these achievements are assisted by improvements in the simulation and modeling of the involved materials and device structures. In particular, process and device technology computer-aided design (TCAD) has become indispensable in the design cycle of novel devices and technologies. It is our sincere hope that the results provided in this Special Issue prove useful to scientists and engineers who find themselves at the forefront of this rapidly evolving and broadening field. Now, more than ever, it is essential to look for solutions to find the next disrupting technologies which will allow for transistor miniaturization well beyond siliconâs physical limits and the current state-of-the-art. This requires a broad attack, including studies of novel and innovative designs as well as emerging materials which are becoming more application-specific than ever before
Circuits Techniques for Wireless Sensing Systems in High-Temperature Environments
RĂSUMĂ Dans ce projet, nous proposons de nouvelles techniques dâintĂ©gration basĂ©es sur la technologie de nitrure de gallium (GaN). Ces techniques permettent de mettre en Ćuvre un systĂšme de transmission de donnĂ©es sans fil entiĂšrement intĂ©grĂ© dĂ©diĂ© aux capteurs de surveillance pour des applications d'environnement hostile. Le travail nĂ©cessite de trouver une technologie capable de rĂ©sister Ă l'environnement sĂ©vĂšre, principalement Ă haute tempĂ©rature, et de permettre un niveau d'intĂ©gration Ă©levĂ©. Le systĂšme rĂ©alisĂ© serait le premier dispositif de transmission de donnĂ©es basĂ© sur la technologie GaN. En plus de supporter les conditions de haute tempĂ©rature (HT) dĂ©passant 600 oC, le systĂšme de transmission sans fil attendu devrait fonctionner Ă travers une barriĂšre mĂ©tallique sĂ©parant le module Ă©metteur du rĂ©cepteur. Une revue de la littĂ©rature sur les applications en environnements hostiles ainsi que sur l'Ă©lectronique correspondante a Ă©tĂ© rĂ©alisĂ©e pour sĂ©lectionner la technologie AlGaN/GaN HEMT (transistor Ă haute mobilitĂ© d'Ă©lectrons) comme une technologie appropriĂ©e. Le kit de conception GaN500, fourni par le Conseil national de recherches du Canada (CNRC), a Ă©tĂ© adoptĂ© pour concevoir et mettre en Ćuvre le systĂšme proposĂ©. Cette technologie a Ă©tĂ© initialement introduite pour desservir les applications radiofrĂ©quences (RF) et micro-ondes. Par consĂ©quent, elle n'avait pas Ă©tĂ© validĂ©e pour concevoir et fabriquer des circuits intĂ©grĂ©s analogiques et numĂ©riques complexes et son utilisation Ă des tempĂ©ratures extrĂȘmes nâĂ©tait pas validĂ©e.
Nous avons donc caractĂ©risĂ© Ă haute tempĂ©rature des dispositifs fabriquĂ©s en GaN500 et des Ă©lĂ©ments passifs intĂ©grĂ©s correspondants ont Ă©tĂ© rĂ©alisĂ©s. Ces composants ont Ă©tĂ© testĂ©s sur la plage de tempĂ©rature comprise entre 25 et 600 oC dans cette thĂšse. Les rĂ©sultats de caractĂ©risation ont Ă©tĂ© utilisĂ©s pour extraire les modĂšles HT des HEMT intĂ©grĂ©s et des Ă©lĂ©ments passifs Ă utiliser dans les simulations. En outre, plusieurs composants intĂ©grĂ©s basĂ©s sur la technologie GaN500, notamment des NOT, NOR, NAND, XOR, XNOR, registres, Ă©lĂ©ments de dĂ©lais et oscillateurs ont Ă©tĂ© mis en Ćuvre et testĂ©s en HT. Des circuits analogiques Ă base de GaN500, comprenant un amplificateur de tension, un comparateur, un redresseur simple alternance, un redresseur double alternance, une pompe de charge et une rĂ©fĂ©rence de tension ont Ă©galement Ă©tĂ© mis en Ćuvre et testĂ©s en HT.
Le systĂšme de transmission de donnĂ©es mis en Ćuvre se compose d'un module de modulation situĂ© dans la partie Ă©mettrice et d'un module de dĂ©modulation situĂ© dans la partie rĂ©ceptrice.----------ABSTRACT
In this project, we propose new integrated-circuit design techniques based on the Gallium Nitride (GaN) technology to implement a fully-integrated data transmission system dedicated to wireless sensing in harsh environment applications. The goal in this thesis is to find a proper technology able to withstand harsh-environments (HEs), mainly characterized by high temperatures, and to allow a high-integration level. The reported design is the first data transmission system based on GaN technology. In addition to high temperature (HT) environment exceeding 600 oC, the expected wireless transmission systems may need to operate through metallic barriers separating the transmitting from the receiving modules.
A wide literature review on the HE applications and corresponding electronics has been done to select the AlGaN/GaN HEMT (high-electron-mobility transistor) technology. The GaN500 design kit, provided by National Research Council of Canada (NRC), was adopted to design and implement the proposed system. This technology was initially provided to serve radio frequency (RF) and microwave circuits and applications. Consequently, it was not validated to implement complex integrated systems and to withstand extreme temperatures. Therefore, the high-temperature characterization of fabricated GaN500 devices and corresponding integrated passive elements was performed over the temperature range 25-600 oC in this thesis. The characterization results were used to extract HT models of the integrated HEMTs and passive elements to be used in simulations. Also, several GaN500-based digital circuits including NOT, NOR, NAND, XOR, XNOR, register, Delay and Ring oscillator were implemented and tested at HT. GaN500-based Analog circuits including front-end amplifier, comparator, half-bridge rectifier, full-bridge rectifier, charge pump and voltage reference were implemented and tested at HT as well. The implemented data transmission system consists of a modulation module located in the transmitting part and a demodulation block located in the receiving part. The proposed modulation system is based on the delta-sigma modulation technique and composed of a front-end amplifier, a comparator, a register, a charge pump and a ring oscillator. The output stage of the transmitter is intended to perform the load-shift-keying (LSK) modulation required to accomplish the data transmission through the dedicated inductive link. At the receiver level, three demodulation topologies were proposed to acquire the delivered LSK-modulated signals
Wide Bandgap Based Devices
Emerging wide bandgap (WBG) semiconductors hold the potential to advance the global industry in the same way that, more than 50 years ago, the invention of the silicon (Si) chip enabled the modern computer era. SiC- and GaN-based devices are starting to become more commercially available. Smaller, faster, and more efficient than their counterpart Si-based components, these WBG devices also offer greater expected reliability in tougher operating conditions. Furthermore, in this frame, a new class of microelectronic-grade semiconducting materials that have an even larger bandgap than the previously established wide bandgap semiconductors, such as GaN and SiC, have been created, and are thus referred to as âultra-wide bandgapâ materials. These materials, which include AlGaN, AlN, diamond, Ga2O3, and BN, offer theoretically superior properties, including a higher critical breakdown field, higher temperature operation, and potentially higher radiation tolerance. These attributes, in turn, make it possible to use revolutionary new devices for extreme environments, such as high-efficiency power transistors, because of the improved Baliga figure of merit, ultra-high voltage pulsed power switches, high-efficiency UV-LEDs, and electronics. This Special Issue aims to collect high quality research papers, short communications, and review articles that focus on wide bandgap device design, fabrication, and advanced characterization. The Special Issue will also publish selected papers from the 43rd Workshop on Compound Semiconductor Devices and Integrated Circuits, held in France (WOCSDICE 2019), which brings together scientists and engineers working in the area of IIIâV, and other compound semiconductor devices and integrated circuits
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MODELLING AND DESIGN OF DIAMOND POWER SEMICONDUCTOR DEVICES
With its remarkable electro-thermal properties such as the highest known thermal conductivity (~22 W/cmâ K at room temperature) of any material, high hole mobility (>2000 cm2/Vâs), high critical electric field (>10 MV/cm), and large bandgap (5.47 eV), Diamond has overwhelming advantages over Silicon and wide bandgap semiconductors (WBG) for ultra-high voltage and high temperature applications (>3 kV and >450 K, respectively). However, despite its tremendous potential, fabricated devices based on this material have not yet delivered the expected high-performance. This is due to three main reasons: (i) the lack of consistent physical models and design approaches specific to diamond-based devices that could significantly accelerate their development; (ii) the absence of shallow acceptor and donor dopant species which has resulted in poor room temperature performance; (iii) the technological issues of the manufacturing process. With the principal aim of modelling the next generation of diamond devices, this Ph.D dissertation endeavours to numerically model the main electro-thermal properties of diamond devices for power electronic applications. Optimized unipolar mode diamond field effect transistors have been designed by means of finite element simulations and their performance has been assessed against the state-of-the-art diamond FETs. Particular attention is given to the static and dynamic properties of deep dopant levels and their effects in WBG semiconductor-based devices. Moreover, by means of a more global comparison technique and through accurate theoretical analysis, diamond FETs and diodesâ performance have been projected and compared with that of GaN and SiC devices. This work concludes with possible implementations of diamond devices in power converters and provides a roadmap of diamond devices for power electronics. These promising results give a new impetus to the rather small, but growing diamond community and enable future research in the field with the goal of bringing diamond to the commercial world.U.K. Engineering and Physical Sciences Research Council for the University of Cambridge Centre for Doctoral Training under Grant EP/M506485/
Physics and Technology of Silicon Carbide Devices
Recently, some SiC power devices such as Schottky-barrier diodes (SBDs), metal-oxide-semiconductor field-effect-transistors (MOSFETs), junction FETs (JFETs), and their integrated modules have come onto the market. However, to stably supply them and reduce their cost, further improvements for material characterizations and those for device processing are still necessary. This book abundantly describes recent technologies on manufacturing, processing, characterization, modeling, and so on for SiC devices. In particular, for explanation of technologies, I was always careful to argue physics underlying the technologies as much as possible. If this book could be a little helpful to progress of SiC devices, it will be my unexpected happiness
Feature Papers in Electronic Materials Section
This book entitled "Feature Papers in Electronic Materials Section" is a collection of selected papers recently published on the journal Materials, focusing on the latest advances in electronic materials and devices in different fields (e.g., power- and high-frequency electronics, optoelectronic devices, detectors, etc.). In the first part of the book, many articles are dedicated to wide band gap semiconductors (e.g., SiC, GaN, Ga2O3, diamond), focusing on the current relevant materials and devices technology issues. The second part of the book is a miscellaneous of other electronics materials for various applications, including two-dimensional materials for optoelectronic and high-frequency devices. Finally, some recent advances in materials and flexible sensors for bioelectronics and medical applications are presented at the end of the book
An Analytic model for high electron mobility transistors.
Thesis (Ph.D.)-University of Natal, Durban, 1986.The last six years has seen the emergence and rapid development of a new
type of field effect transistor, the High Electron Mobility Transistor
(HEMT), which offers improved performance in both digital and analogue
circuits compared with circuits incorporating either MEtal Semiconductor
(MES) or Metal Oxide Semiconductor (MOS) FETs. A new physically-based
analytic model for HEMTs, which predicts the DC and RF electrical
performance from the material and structural parameters of the device,
is presented. The efficacy of the model is demonstrated with comparisons
between simulated and measured device characteristics, at DC and
microwave frequencies.
The good agreement with experiment obtained with the model indicates
that velocity overshoot effects are considerably less important in HEMTs
than has been widely assumed, and that the electron transit velocity in
submicron devices is approximately 10
cm/s, rather than around 2x10
cm/s.
The Inverted HEMT, one of the major HEMT structural variants, is
emphasized throughout this work because of its potential advantages over
other variants, and practical results from 0.5 micron gate length
Inverted HEMTs are presented